Just to avoid any potential for confusion - there is not a specific turbo "drive" - the Turbo part is the fins and fin masts which are an optional replacement for the standard fins and fin masts on the one and only Hobie Mirage Drive.

I am not certain as to exactly when the Mirage Drive was introduced to the market but Mirage Drive inventor, Gregory S. Ketterman and assignee R.R. Sail Inc. filed patent application #08/903,020 for their "flappers" on 7/30/1997 and was granted patent #6,022,249 (I believe on 2/8/2000).http://patft.uspto.gov/

Check out Ketterman's R&D video for his "flapper mechanism" that he has uploaded to his own YouTube channel:[youtube]http://www.youtube.com/watch?v=Iu7K93lmQmo&list=UUt4Zvd10j-m6-ymxGsXsYzg&index=4&feature=plpp_video[/youtube]

I believe the Mirage Drive powered Hobie kayak was first sold in the fall of 1997. It had canvas "sails". There have been dozens of improvements since then (almost all of which can be retrofitted to older models), but the basic concept and operation has not changed.

The first Turbofins were available Spring of 2006. They are now in what can be described as their fifth generation.

I think it depends on the type of patent. Design patents used to last 14 years, with product patents lasting somewhere around 17 to 20 years. I think there are some specific cases where they may even extend beyond 20 years.

No doubt Hobie, and their competitors, know when the Mirage Drive patent is up.